Lighting devices, particularly for signal lamps, have heretofore been implemented in a wide variety of ways. Rotating effects of the kind used in blue or orange lights on vehicle roofs have heretofore been achieved primarily by means of a conventional incandescent bulb with an associated reflector that is set in rotation by a motor. The reflector is used for beam forming. A device of this kind is onerous and trouble-prone.
A number of solutions now exist for signal lamps with flashing and rotating effects in which light-emitting diodes (LEDs) are used to generate light.
For example, an LED-based signal lamp is known from the document WO 02/066889 A1. In this signal lamp, LEDs are disposed on printed circuit boards, which themselves are then arranged in a ring around a light body. The advantage of such a signal lamp utilizing LEDs is that rotating and flashing effects can be achieved by electronically driving the individual LEDs without the need for mechanical rotation of part of the lighting device to produce rotating effects. A further advantage of using LEDs is their service life and low maintenance requirements.
The document U.S. Pat. No. 5,806,965 describes an arrangement in which the LEDs are mounted on a curved surface.
In arranging LEDs on curved surfaces, the conventionally used standard placement techniques designed for planar printed circuit boards (PCBs) cannot be utilized. Arranging planar pieces of PCB in a curved surface shape necessitates onerous wiring of the individual pieces of board. This requires more effort, and higher costs are the result.